The invention relates to avionics and, more particularly, to a system and method for simulating air mode and ground mode of an airplane.
Maintenance procedures on airplane systems sometimes entail that the system be placed in a state that is indicative of the airplane being on the ground or in the air. The state indicative of the airplane being in the air is referred to as an xe2x80x9cair mode,xe2x80x9d and the state indicative of the airplane being on the ground is referred to as xe2x80x9cground mode,xe2x80x9d
Air mode and ground mode determinations are typically made from signals generated by sensors that sense parameters indicative of whether the airplane is in the air or on the ground. For example, typical sensors may include proximity sensors, such as variable reactance sensors, that are mounted on an airplane""s main landing gear and nose gear, When the airplane is on the ground, the main landing gear and the nose gear compress due to the weight of the airplane. This compression brings a target mounted on the gear closer to its associated proximity sensor, and the proximity sensor outputs a signal that is indicative of the airplane being on the ground. When the airplane is in the air, the weight of the airplane is off the main landing gear and the nose gear, and the gear are no longer compressed, The target is displaced from the proximity sensor such that the proximity sensor no longer detects the presence of the target, and the proximity sensor outputs a signal that is indicative of the airplane being in the air.
Some maintenance procedures require that the air mode be simulated while the airplane is actually on the ground. In known air/ground systems, simulating an air mode when the airplane is on the ground entails overriding the proximity sensors. For example, it is known to insert a piece of aluminum between a variable reactance proximity sensor and its target. Placing aluminum between the variable reactance proximity sensor and its target lowers the inductive coupling between the proximity sensor and its target, such that the inductive coupling is about the magnitude of coupling that results when the airplane is in the air and the gear is not compressed. Thus, an air mode signal is simulated. However, insertion and alignment of the aluminum pieces before performance of the maintenance procedure, and removal of the aluminum pieces after completion of the maintenance procedure, introduce significant time and labor expenses.
Similarly, some aircraft maintenance procedures require the landing gear to be raised. Raising the landing gear while the airplane is on the ground requires that the airplane be supported by jacks. Such an evolution is time and labor intensive, and is preferably conducted in a sheltered environment, such as an airplane hangar. Because of time and schedule constraints, and because of considerable cost considerations, it is desirable to minimize time spent performing maintenance procedures in hangars.
However, in known systems, simulating a ground state entails inserting material, such as steel, to increase the inductive coupling of the variable reactance proximity sensors. Thus, the time and labor expenses associated with simulating air mode in known systems is also introduced when simulating ground mode in known systems. Therefore, known methods of simulating ground mode lengthen, rather than shorten, time spent in hangars while performing maintenance procedures.
There is thus an unmet need in the art for an airplane air/ground system that simulates an air mode and a ground mode without the time and labor expenses required to insert materials into the proximity sensors.
The invention is a system and method for simulating an air mode and ground mode of an airplane. The system and method of the invention simulates an air mode and a ground mode without the time and labor expenses required by methods currently known in the art.
According to the invention, a system for simulating an air mode and a ground mode of an airplane is provided. The air mode is a state of the airplane when the airplane is in the air, and the ground mode is a state of the airplane when the airplane is on the ground, The system includes means for sensing parameters indicative of whether the airplane is sensed in the air or sensed on the ground. Means for determining whether the airplane is sensed in the air or sensed on the ground is provided. The determining means is responsive to the sensing means, and the determining means outputs a signal that is indicative of a sensed air mode or a sensed ground mode. Means for interfacing with an operator is also provided. A simulated air mode and a simulated ground mode are selectable via the interface means. Means for overriding the signal output from the determining means i.% provided and the overriding means outputs a signal that is indicative of the simulated air mode or the simulated ground mode in response to a selection from the interface means. The overriding means outputs a signal that is indicative of the sensed air mode or the sensed ground mode when the simulated air mode or the simulated ground mode is not selected.